1 Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, Amsterdam, The Netherlands. h.brand@acta.nl.
2 Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, Amsterdam, The Netherlands. z.assy@acta.nl.
3 Saliva Clinic of the Dutch Institute for Salivary Research, Bunschoten, The Netherlands. casperbots@gmail.com.
4 Department of Oral and Maxillofacial Surgery/Oral Pathology, Amsterdam UMC, Location Vrije Universiteit Amsterdam, Amsterdam, The Netherlands. d.jager@amsterdamumc.nl.
5 Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, Amsterdam, The Netherlands. f.bikker@acta.nl.